Reykjavik > golden circle > Vik

Are you trying to do this all in one day? It doesn't look like you've accounted for
driving time, or the likelihood of seeing something spontaneously that you want
to stop for.

For all the effort to get there, unless you have constraints you have not mentioned,
take at least 2 days to see and enjoy.

You also need to add time for finding and paying for a parking space, and negotiating (some) unpaved, potholed, un-lined, anarchic parking lots. (South coast, for example.) There are lines for food, and as noted, distances between attractions are huge. Some waterfalls are a 15- minute unpaved walk from parking. Some waterfalls have a climb to get there. Have you looked at Rick's book?

Where are you starting the day, Reykjavik or will you already be staying in the Golden Circle? I ask because that extra time of driving may make a difference in how much time you have.

Bruarfoss is good, but if you want to do the hike add in another 30 minutes. The hike is really nice and you see a few other waterfalls.

Geysir, that is about right for time.

Gullfoss, for the falls themselves yes about 45 minutes. The gift shop/cafe there though is very good so if you do anything in there allow at least another 30 minutes. FWIW it is one of the best gift shops in the country and has a wide selection.

Seljalandsfoss--I would say 30-45 minutes, but more if you wander down the path to Gljúfrabúi which is a waterfall inside a little canyon. This one gets busy because the entrance is so small, but we enjoy it. You do want good solid boots for that and they may still get wet as you walk as close to the rock wall as you can, but depending on the water you still may get soaked. People are really good about helping each other etc.

Skogafoss itself is about a 30-45 minute stop, but if you go up the over 500 steps then it is a whole new world. You can go for miles upon miles and see waterfall after waterfall. So obviously if you choose that you will need much more time. You could though just walk to the top and wander a bit and then head back down. If nothing else at least add in Kvernufoss here too. It is just down the road from Skogafoss as you turn off the main road. Go straight and it will be on your right. It is about a 10-15 minute walk to the falls, but FAR fewer people than any of the other places and really beautiful. You can also walk under the waterfall here too. There is a nice museum at this location, but it is the outdoor area of it that we really like. If you can fit this side stop in at all, I highly recommend it.

Thingvellir is the one that is tough to say. Some people spend half a day there, others do a quick look for 15 minutes and call it good. Plus there are different locations within the park.

If you are coming from Reykjavik, then you probably won't have time to do everything I mentioned, but at least you know a bit more of what your options are and can see what interests you the most.

The gift shop/cafe there though is very good so if you do anything in there allow at least another 30 minutes. FWIW it is one of the best gift shops in the country and has a wide selection.

This is true; it is a nice gift shop, but I would not buy the Saltverk jars of salt there, as you can get them much cheaper at a Bonus or Kronan grocery. I came back with quite a few jars of it, and laughed the other day when I was at our local co-op and they had it there for four times the amount I paid for it at Bonus.

Mardee--Yes the Saltverk ones are so much less at Bonus. I like a different brand though, the ones with the variety of flavors like Rhubarb, Arctic Thyme etc, and Bonus nor the duty free at the airport carries those. I always stock up and family asks me to bring them back.

My family did a road trip in Iceland a few years ago. It took us a full day for the Golden Circle from Reykjavik. The southeast coast to Vik took another day. There are so much to see on the way.

If your time is limited, I'd prioritize the south coast and Snæfellsnes Peninsula over Golden Circle if your interest is in nature. For the touristy spots, Golden Circle will be the way to go.

Here's more detail about our road trip if you're interested.
https://agrandersight.wordpress.com/destinations/europe/iceland/

Spend 3 hours at Skogafoss so you can walk part of the trail at the top. We thought it was one of the most beautiful easy hikes there.

Thank you so much for the information you shared. They are so helpful. We decide that to spend one full day for golden circle, and stay overnight around selfoss or hela. Then continue to Vik the next day!